Fuse link



Nov. 30, 1943.

C. B. ANDERSON FUSE LINK Filed May 20, l942 %f za i O f i 2 Sheets-Sheet l ;7 19 %w /5 g z Z ATTOENEY.

Nov. 30, 1943. c B so 2,335,229

FUSE LINK Filed May 20. 1942 2 Sheets-Sheet 2 33 l 32 /jjyj IN VENT OR.

ATTORNEY.

Patented Nov. 30, 1943 2335329 rosa um:

- Clarence B. Anderson. Tllsa. Okla..

assignoto Line Material Company, Milwaukee, Wis.. a

corporation of Delaware Application May zo, 1942, Serial No. masi 4 Claims. cc. zoo-135) This invention relates to protective devices i'or electric circuits and has to do particularly with replaceable fuse-links for use on power lines.

The kind of fuse structure most widely employed on power lines of intermediate voltages is of the so-called expulsion type which employs a fuse-link having a button-head contact member at one end which is designed to be firmly clamped edgewise between a pair of contact elements forming component ,parts of an expulsion cartridge. Fuses of that character are used in very great numbers, and the button-head fuselinks are standard equipment which the utility companies carry in stock for replacement purposes. There is, however, a somewhat difierent kind of fuse structure, less widely used, which requires a ruse-link devoid of the button-head contact and having instead another type of terminal-usually one having an external thread. otherwise, the ruse-links are functionally identical and interchangeable.

It is something of a nuisance and extra expense to the utility companies to be obiiged to stock difierent kinds of fuse-links of like ratings in order to be able to service the diierent kinds of fuse structures; and with a View to meeting that situation it has previously been proposed to provide a iuse-link having an externally threaded terminal, together with a button-head internally threaded contact member removably secured to the external thread of the terminal. such a ruse-link is adaptable to both kinds of fuse structures referred to above but is obiectionable for the reason that the threaded joint introduces an additional point in the circuit where looseness, oxidation, or corrosion may give rise to contact resistance, which would cause heat to be generated near the fusible section, and which, in turn, would render inaccurate the caiibration oi the link.

The primary object of th present invention is to provide a fuse-link which is adaptable for use alternatively in either of the aforementioned kinds or fuse structure, but having no intermediate joint between the button-head contact and the fusible section which, through corrosign, oxidation, or looseness, might give ri ietrimental contact resistance.

To that end, the novel ruse-link hereinaiter described is characterized by the provision o! a terminal having an integral button-head contact and, in addition, an externally threaded portion which performs no function when the fuse-link is used in its unaltered form, but which renders the fuse-link adaptable for use in an alternative type of fuse structure by merely cutting of! a portion of the ruse-link terminal-which portion includes the aforernentioned button-head contact. The new terminal preferably is so designed that conversion thereof can be efiected with a pair of wire-cutting pliers-leaving no burr to interfere with the externally threaded portion of the terminal. Thus, the invention eliminates the necessity of stocking two kinds of fuse-links, without resorting to an expedient entaiiing the presence of an extra joint with its imminent prospect of fuse failure resulting from contact resistance.

In the drawings:

Fig. 1 is an elevational View, partly in section, showing a i'use tube or cartridge and appurtenant parts, together with a fuse link thereinbeing representative oi one type of expulsion iuse in which fuse links of the present invention are employable;

Fig. 2 is an enlarged detail of the upper end of the fuse tube shown in Fig. 1;

Fig. 3 is a longitudinal section of the upperend-portion of a fuse tube showing the fuse iink of Fig. 2 altered to meet a situation which previously required the use of a special fuse link;

Fig. 4 illustrates a fuse link of the enclosed type embodying the present invention; and

Fig. 5 shows a fuse link of the non-enclosed type which also is in accordance with the invention.

In Fig. 1 there is shown a fuse tube and appurtenant parts corresponding to Fig. 3 of United States Patent 2,269,130 granted to William O. Schultz January 6, 1942, and therein fully described. The i'use tube is here identified by reference numeral ID. The other illustrated parts copied from the Schuitz patent are an upper contact member or errule ll, a screw cap [2, a thumb nut !3, an eyelet !4, and other mechanical parts which it is unnecessary for the purposes of the present invention to identity.

A fuse-link |5 corresponds in function to that shown in Fig. 3 of the aforementioned Schultz patent, but difiers from that of Schultz in conformity with the present invention. Fuse-link !5 is shown in detaii in Fig. 2. It comprises an upper terminal member I 6, a. fusible wire l'l, a strain wire s, a lower terminal s, a fibre sleeve 20, and a flexible leader 2| the free end of which is secured by means of thum-nut I3. The upper terminal member includes a button-head contact member 22, a flat shank portion 23, notched at 24, an externally threaded coupling portion 25, and a portion 26 of reduced diameter. The latperforms no function in the structure of Fig. 1- s but renders the fuse link capable of alteration in such manner as to adapt it for use in a fuse structure which otherwise would require the provision of a special fuse-link.

Fuse-link ofFigs. 1 and 2.is to all intents and purposes a conventional fuse-link which is fully interchangeable with standard links ordinarily employed in fuses like that of Fig. 1,. But a standard fuse-link could not be employed in the *assemblage of Fig. 3 whereas fuse link |5 of Figs.

1 and 2 can easily be 'altered to render it useable in the assemblage of Fig. 3 as presently will be explained.'

Referring now to Fig. 3, there is shown a fuse tube 21 together with an upper contact member or ferrule 28 and screw cap 29 which are substantially identical with the 'corresponding parts shown in Figs. 1 and 2 except that it may be assumed that tube 21 is substantially longer than tube o. But the fuse-link assemblage shown in Fig. 3 differs radically from that of Figs. 1 and 2 although it includes fuse-link [5, previously described, in altered form.

The fuse-link assemblage shown in Fig. 3 is identified as a whole by reference numeral 30 and it includes, as a Component part, a fuse-link 3! which is fuse-link !5 of Fig. 2 modified in that 'the upper terminal !6 of fuse-link l-has been cut nected a !usible wire 43 and a strain wire 44 which are similarly. connected also to a lower terminal 45. Two parallel flexible leaders 46 and 41 are connected at the upper end to lower terminal 45. The'fusible wire and strain wire together with the lower terminal and the upper ends of the fiexible leader are enclosed within a fibre sleeve 48, the upper end 'of which is Secured to the upper'terminal through the medium of an adapter bushing 49 on which it is pressed and which in tum is pressed onto the reduced diame ter portion 42 of the upper'terminal.

The fuse-link of Fig. 4, as shown, is adapted for use, without alteration, in a fuse assemblage similar 'to that of Figs. 1 and 2. By cutting oi! the upper-terminal 31 just above the threaded coupling portion 4| the fuse-link becomes adapted for use in a fuse assemblage like that of Fig. 3. The cutting off operation is usually performed with a pair of lineman's wire-cutting pliers.

Fig. 5 portrays a modification of the fuse-link I 5 of Fig. 2. In this case the fibre sleeve ha's been 4 identical with fuse-link IS, as will be seen upon threaded dependent shank 33 to which is Secured the upper end of a coil spring 34, the lower end of which is attached to an adapter 35, which is internally threaded at its lower end to engage the externally threaded upper end 25 of fuse-link 3l. Contact button 32 and adapter 35 are electrically interconnected by a fiexible conductor 36 which passes axially through spring 34. Spring 34 is normally under tension placed thereon by virtue oi flexible conductor ZI being drawn taut.

Heretofore fuse-links similar to link 3| had been available for use in fuse assemblages such as that illustrated in Fig. 3; and fuse-link 3| is not, per se, novel save that it is produced by altering the novel fuse-link !5. v

It will be seen that the invention consists in providing a fuse-link which can be used without alteration in the fuse structure of Figs. 1 and 2,

and which can also be used, after severing a part of the upper terminal, in the fuse structure of Fig. 3-the latter having previously required a specially designed fuse-link.

Fig. 4 shows a fuse-link designed to carry a heavier current than the link of Fig. 2 and differ- ,ing from the latter in minor respects. Here the upper terminal 31 is turned from bar stock and has no flat shank such as portion 23 of Fig. 2. The upper terminal is in one piece and comprises a button-head, contact 38, a cylindrical shank portion 39 having a reduced portion 40 just above an externally threaded coupling portion 4 l below which is another portion 42 of reduced diameter. To the lower end of the upper terminal are concomparison of the two. In Fig. 5 the upper terminal comprises a button-head contact member 50, a flattened shank portion 5! having a notch 52, and a threaded coupling portion 53 to which are attached fusible wire 54 and strain wire 55. The lower terminal is identified by numeral 56 and the exible leader by numeral 51.

Fuses and fuse-links, generally, of the kind-here described are well known, and since there is presented nothing which is functionally novel, it is thought superfiuous to describe the mode of operation of the fuse-link beyond that which is essential to a clear understanding of the invention on the part of those who are skilled in the art.

The word "sever" is hereby defined for purposes of the present specification and appended claims as meaning to cut apart or break apart, and is not synonymous with the word "separate" or, the word "disjointJ' What is claimed is:

1., A fuse-link comprising a fusible section and a terminal connected to one end thereof, said fuse-link being operative, without alteration, for use in a certain pre-designated fuse assemblage, said terminal having a contact portion remote from said fusible section and a threaded portion intermediate of said contact portion and said fusible section, said fuse-link being adaptable for use in a certain second pre-designated fuse assemblage by severing said terminal ,between said contact portion and said threaded portion, said threaded portion being operative for engagement by' a complementarily threaded element forming apart of the second-mentioned fuse assemblage, but so operative only when said terminal has been severed as aforesaid.

2. A fuse-link comprising a fusible section and an elongated terminal connected end-to-end therewith, said terminal having a contact button at the end thereof remote from said fusible section, a portion of said terminal including said contact button being severable -from the remainder of said terminal, said terminal including an externally threaded coupling portion which is not a part of the severable portion of the terminal, said contact button being operative as a coupling means between the fuse-link and other co-operating parts of a, certain pre-designated fuse assemblage including said fuse-link unaltered, said externally theaded coupling portion being operative, after severance of the severed portion of said terminal, as a, coupling means between the fuse-link so altered and other co-operating parts of a second pre-designated fuse assemblage including the altered fuse-link, which second fuse assemblage is not adapted for inclusion of the unaltered ruse-link.

3. A fuse-link comprising a fusible section and an elongated terminal connected end-to-end therewith, said terminal including a. contact button at the end thereof remote from said fusible section, an externally threaded coupling portion spaced from said contact button and disposed intermediately of said contact button and said fusible section, an elongated shank portion interconnecting said contact button and said externally threaded coupling portion, and a flexible leader connected to said fusible section at the end thereof remote from said terminal, said fuse-link being operative by reason of said contact button for inclusion in a certain pre-designated fuse assemblage and operative by reason of said threaded coupling portion for inclusion in a. different pre-designated fuse assemblage.

4. A fuse-link comprising a fusible section, an elongated terminal connected end-to-end in series with said fusible section, a fibre sleeve Secured at one end to said terminal and surrounding said fusible section, said terminal including a contact member at the end thereof remote from said fusible section and a threaded coupling portion intermediate said contact member and said fusible section, said terminal also including a shank portion between said contact member and said threaded coupling portion, said shank portion being severable adjacent said threaded coupling portion to render the fuselink useable as a component part of a fuse assemblage in which it otherwise is not adapted for inclusion, said fuse-link, including said contact member, being suitable for inclusion in another designated fuse assemblage.

CLARENCE B. ANDERSON. 

